Sunday, October 21, 2012

An Experiment You Can Do at Home: A Balloon-Powered Craft

An Excerpt from The Lost Laboratory of Professor Xandiver
Once all of the boxes had been loaded in the raft, and everyone had seated themselves securely beside them, one of the sailors stepped in the front and started adjusting some strange-looking valves on the platform.
“What‘s that?” asked Jake.
Anicia looked over at him. “Oh, those control the pressure inside the balloon.”
“The balloon?” asked Jake.
“Well, it’s not really a balloon,” corrected Ms. B. “It’s bigger and thicker, but the concept is the same. Professor Xandiver invented it.”
            “Who’s Professor Xandiver?” asked Molly.
Jake glared at his sister then looked up at the balloon-like contraption hanging over them. “More importantly, just what does this balloon do?”
“It runs the raft,” Anicia answered in her usual formal tone. “Do you see the bar to which it is attached?” 
Molly looked up. She hadn’t noticed the huge balloon connected to a bar floating over the raft. How did I miss that?, she thought.
“The raft is also attached to that bar. A cable runs through the middle and extends from here to the manor entrance along the stream. The driver adjusts a valve, releasing the air pressure from the balloon, and we shoot out at a great speed over the stream.”
“Wow, just how fast are we talking about here?” Jake asked.
Anicia smiled slyly. “You will see.”

An Experiment You Can Do at Home

The Balloon-Powered Craft
If you would like to make your own miniature version of the balloon-powered craft that Lord Ravenworth uses to bring goods and passengers through the caves from his ship to his manor, just follow the directions below.
Easy version:
Items needed
   Two small cotton threads (one shorter one to tie to the boat and one longer one to run the length of your tub or pool.)
   One straw (Bendy straws do not work as well as regular straight straws.)
   One balloon
   One small toy boat
   One large tub or pool
   Tape

1.  Run both of the threads through the straw.
2. Tie or tape both ends of the shorter thread to both ends of the boat to attach it to the straw. (Make sure the thread is connected to the center of each end, so the boat will float straight.)
3. Set up a mini clothesline by tying or taping both ends of the longer thread to a wall or other solid support on both ends of the tub or pool. Adjust the height so that the boat just rests on the water. Make sure the thread connecting the boat is not slack and the thread tied to the wall or supports is pulled taut.
4. Next, blow up the balloon and hold the end closed without tying it.
5. While you are still holding the balloon closed, tape it to the top of the straw.
6. Once the balloon is securely attached to the straw, let the balloon go. It will fly quickly from one end of the thread to the other.

Advanced version:
1. Follow the directions above except replace the thread holding the boat to the straw with something more solid and steady such as small light pieces of cardboard or wood. You want the boat to be firmly attached to the straw, so it is stable and moves smoothly and unwaveringly through the water.
2. Replace the thread that you use as a line with something thicker and steadier such as a leather string or small wooden or metal bar. Just make sure that it is small enough to enable the straw to slide smoothly over it.
3. Measure carefully to ensure that the boat just sits on the water before attaching the line to both ends of the pool. If it sits too low in the water, it won’t run as well.
4.  Instead of holding the balloon closed, go ahead and tie it. When you are ready to set the boat in motion, get a straight pin and poke a small hole in the boat. It needs to be big enough to let enough air escape to move the boat, but small enough to make the air last longer, so that the boat can travel farther.

Now, you are ready. Put your own miniature passengers in the boat and watch their ride.

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